TRW Low Maintenance Rifle

The TRW Low Maintenance Rifle or LMR was a proposed insurgency weapon designed by TRW Inc. (formerly Thompson Ramo Wooldridge) of the United States during the Vietnam War. The intent was to produce an easy-to-use and operate firearm which could be disseminated to insurgent forces supporting the United States' military interests. The design utilized the same 5.56×45mm NATO ammunition and STANAG magazines as the M16 rifle. It would have been equipped with the M6 bayonet along with its M8A1 scabbard.

TRW Low Maintenance Rifle
The TRW LMR. Minor differences exist in the stock, handguard, and sights given the various prototypes made.
Type	Full-automatic fire only insurgency assault rifle
Place of origin	United States
Production history
Designer	Donald A. Stoehr (1927-2011)[1]
Designed	February 1971[2]
Manufacturer	TRW Systems Group
Unit cost	Specified cost of less than $130 (1971),[3]
Produced	1971—1973
No. built	fewer than 10.
Specifications
Mass	Unloaded: 3.30 kg (7.3 lb)[4] Loaded: 3.64 kg (8.0 lb)[4]
Length	871 mm (34.3 in)[4]
Barrel length	493 mm (19.4 in)[5]
Cartridge	5.56×45mm NATO
Action	Roller locked open bolt gas-operated long-stroke piston
Rate of fire	450 RPM Cyclic[4]
Muzzle velocity	3,248 ft/s (990 m/s)[4][5]
Effective firing range	460 metres (1,510 ft)[4]
Maximum firing range	2,425 metres (7,956 ft)[5]
Feed system	20, 30-Round STANAG magazine[4]
Sights	Rear: Two-position flip aperture Front: Adjustable post

Development began in 1971, and ceased in 1973 with the weapon never having been fielded.